This training grant in developmental endocrinology and metabolism at Children's Hospital Boston intends to provide funding for postdoctoral fellows to engage in research training leading to independent careers in academic pediatric endocrinology. Trainees enter the program with either the MD, MD/PhD or occasionally the PhD degree, and are selected from highly qualified pediatric endocrinology fellows at Children's Hospital. The 28 trainers include 13 pediatric endocrine physician-scientists (including 5 MD/PhDs), 13 physician-scientists of other disciplines, and 2 PhD scientists. Children's Hospital is the major training site, along with laboratories at Massachusetts General Hospital, Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, and Joslin Diabetes Center. The major areas of research emphasis in this training grant include clinical, translational and basic laboratory research in diabetes mellitus, obesity, neuroendocrinology, thyroid disease, bone health, stem cell biology, bioinformatics, ion transport, and human outcomes research. Training consists of didactic courses, including in quantitative methods and the ethical conduct of research, and an intensive period of individually mentored research. The intended average duration of training is two years. Of the 15 trainees during the past 10 years who have completed this training program, all but 1 are faculty in academic pediatric institutions (1 Professor, 2 Assistant Professors, 9 Instructors) and 2 are in industry. Of these, 3 have had independent NIH K awards, and 1 has an R01. Their record of publication is strong. This program takes advantage of the breadth of scientific expertise of the training faculty within the Division of Endocrinology, as well as in the larger Children's Hospital Boston community and surrounding Harvard environment.